Starter means for hydraulic devices



N0V 6, 1951 T. w. MORAN STARTER MEANS FOR HYDRAULIC DEVICES Filed June 26, 1948 FC. x

INVENTOR. T HERON W. MORAN HTTORHEXS Patented Nov. `6, 1951 STARTER MEANS FOR HYDRAULIC DEvIcEs Theron W. Moran," Encino, Calif., assignor to A. M. Conley, doing businessas The Conley Company, Los Angeles, Calif.

v Application June 2s, 194s, serial'No. 35,504 y My invention relates to starter means for hydraulic devices, and more particularly to starter means for hydraulic lifts, and included in the objectsof my invention are:

First, to provide a means which enables a positive displacement pump to be employed for the purpose, of actuating a hydraulic lift or other hydraulic devices without encountering shock loads or excessive initial acceleration when the pump pressure is applied to the device, this being avoided by by-pass arrangement which is gradually and controllably throttled so as to avoid shock loads and enable the hydraulic device to start smoothly and easily. n

Second, to provide a means of this character wherein the rate of initial acceleration of the hydraulic device may be readily and easily controlled or adjusted.

Third, to provide a means of this character which is particularly suited for use in conjunction with hydraulic lifts and insures smooth opera'tion even though the load may vary over wide ranges.

Fourth,`to provide a, means of this character which is particularly dependable in its operation.

With the above and other objects in view as may appear hereinafter, reference is made to the accompanying drawing in which:

The gure is a diagrammatic view of my starter means for hydraulic lifts, portions of the by-pass valve being shown in section.

A fluid supply system for hydraulic lifts includes a surge or reservoir tank I lwhich is connected by a pipe line 2 to the intake of a pump 3, the outlet of which is connected by a suitable pipe line 4 to a hydraulicdevice or lift (not shown). A check valve 5 is provided in the supply line 4V so that the hydraulic lift may be raised by action of the pump, but the hydraulic uid cannot backflow through the pumpto the surge tank. In practice a separate line' (not shown) by-passes the check valve so that the hydraulic lift may be controllably lowered.

In the exercise of my invention, I provide a by-pass line lIi which joins the supply line 2 and the supply line 4. Mounted in the by-pass line 6 is a by-pass valve 'I. The preferred type of bypass valve comprises a tubular valve body 8 in which is fitted a core 9. The core 9 is tubular but divided by a central bulkhead I0. Annular rows of slots II and I2 are provided in the walls of the core I9 at opposite sides of the bulkhead I0 so that fluid may pass around the bulkhead by flowing radially outwardly through one set of slots and radially inwardly through the other set of slots. Interposed between the core 9 and the 4 Claims. (Cl. 10S-39) 'or similar yieldable material.

valve body 8 is a valve tube I3 formed of rubber The valve tube is adapted to be constricted about the bulkhead Ill to close the by-pass valve. This is accomplished by introduction of fluid into an annular pressurey chamber dened by the valve tube and the confronting walls of the valve body. This chamber is intersected by a port I4 which is connected to a small control line I5. The 'control line returns to the valve body at the intake side thereof andv communicates with a port I6. Interposed in the control line 'I5 is a throttle valve II. An air chamber or cushion chamber I8 may communicate with the control line and augment in effect thevolume of the pressure chamber dened be-` tween the valve tube I3 and valve body 8.

Operation of my starter device for hydraulic lifts is as follows:

When the pump 3 is idle backiiow from the hydraulic lift is prevented by check valve 5. However, due to the fact that the pump 3 is not itself a check valve but instead will by-pass iiuid in either direction when idle, the pressure on both sides of valve 'I corresponds to the head of munic'ation-with the chamber I8. Thus, initially,

the entire output of the pump is by-passed through the valve 'I.

1 The attendant pressure differential between the upstream side of the valve 'I at port I6 and; the chamber I8 results in flow through the throttle valve I1, Acausing a gradual building upv ofleback pressure in the cavity which surrounds the valve tube I3. Such pressure constricts the tube I3, throttling the by-pass valve 'I. The rate at which the by-pass valve closes depends upon the setting of the throttle valve I'I. The gradual rise in pressure in line 4 insures a soft or gradual acceleration of the hydraulic lift connected therewith. Also, by reason of the fact that the initial output of the pump is by-passed, the pump motor (not shown) is not required to start under load, but instead may reach its optimum running speed before full load is applied, that is, before the by-pass valve is re-closed.

When the pump is stopped, the excess uid 1S It should be observed that the pump motor is controlledA by suitable switches located :in Aconvenient relation to the hydraulic lift or other hydraulic device.

It should be observed that the air .chamber` lis shown diagrammatically and therefore the llexible membrane conventionally used to separate the air and liquid in an air chamber iS omitted. In actual practice, such Amembrane is used to prevent gradual absorption of air in the liquid. However, it should be 'pointed out `'that even Without the provision of the diaphragm, the system will operate for several days or several Weeks, depending on the liquid used.

vI-Iaving fully described my invention, it is Luiderstood that I do not wish to be limited to the details herein Vset forth, but my invention is of the full scope of the appended claims.

Iclaim: p v

vl. An actuating means for hydraulic lifts Ycomprising: a positive displacement pump adapted toy deliver fluid to a hydraulic device; 'a 'by-'pass valve `connecteci across said pump,`said valve includin'g 'a valve body, a sleeve Within Said body and defining therewith an "annular pressure chamber, a valve core within said sleeve and including a bulkhead engaged by said sleeve when said sleeve is constricted by iuidpressure said chamber thereby to close said valve; a cushion chamber member in communication with said pressure chamber, a flow line communicating with said pressure chamber and cushion cham- '.ber member and with Vthe-output side of said pump; and athrottle valve in said flow line, said cushion chamber member *adapted to receive liqiuidfrorn said pressure chamber upon initial operation of said pump to permit ow through said Eby-pass valve, said throttle valve adapted to cause controlled increased pressure in said cushion chamber member and pressure chamber and thereby cause said valve to reclose gradually on continued operation of said pump. Y

2. An actuating means for hydraulic lifts comprising': apositive displacement pump adapted to deliver fluid to a hydraulic device; a-by-pass valve Vconnected across said pump, said valve in.- cludinga valve body, a sleeve within said body and defining therewith an annular pressure chamber, a valvecore Within said sleeve and including a bulkhead engaged by said sleeve when said sleeve is constricted by fluidwpressure in said chamber thereby to close said Valve; and means including a by-pass line to the output side of said pump, a restrictor valve in said line and a ushion chamber lin communication vwith said :pressure chamber and adapted Yto relieve pressure in said pressure chamber on initial starting of said pump, thereby to open said by-pass valve and thereafter receive fluid through said restrictor valve to repressure said pressure chamber and effect gradual re-closing of said by-pass valve.

3. In a starting apparatus for hydraulic devices whereina pump employed to operate said hydraulic device and a check valve prevents backy:flow from said device through said pump when said pump is idle, the combination of a by-pass Yi'lalv'e connected across said pump, said by-pass valve including a valve body defining a ow passage', ayieldable 'sealihg member normally closing said ilow passage, said sealing member and valve body dening a uid receiving pressure 'chamber controlling said sealing member; and a cushion chamber member in substantially free communication with said pressure chamber and in restricted communication with the output side of said said cushion Vchamber' member adapted to receive huid from said pressure chamber when said pump Yis initially operated thereby to permit opening of said sealing member and to accumulateslowly Vpressure from the output side of said pump tos'upp'ly said pressure chamber and gradually7 re-'close ysaid lsealing member.

4. In a Vsl'fating apparatus for hydraulic devices 4wherein a 'pump is employed to'operate said hydraulic device anda 'check valve prevents backflow from said device through said pump when saidlp'ump 'is i'dle, the combination of: a by-pass valve connected across said pump 'and including a normally closed seal means adapted to open in response to 'flid'pres's'ure Within said by-pass valve, yand a fpres'sure 'responsive means for closing said seal 'means 'in 'opposition `t`o `pressure in said byrpass valve; a cushion chamber member in substantially free communication with said pressure responsive means, and in restricted communication with 'the output side of said pump; said cis'hion'chamber vadapted to receive fluid from said pressure responsive means 'upon initial application of pressure against said seal means thereby lto 'open said by-pass valve on starting of said'piump, said cushion chamber and pressure responsive 'means adapted to accumulate pressure during operation of said pump therebyy to 'gradually re-close said by-'pass valve.

THERON W. MORAN.

REFERENCES forrED The following references are of record in the lc'of this patent:

UNITED STATES PATENTS Number n Name Date $94,102 Banjock July 21, 1908 2,331,291 Armin T oct. 12, 1943 2,353,143 Bryant July 11, 1944 2,360,873 Grove Oct. 24, 1944 

